A driver may cause a vehicle to undergo a hard turn, a quick turn, or a series of hard and quick turns when encountering various driving conditions and situations. Such conditions can be experienced during high-speed maneuvers. Quick maneuvers also can occur to avoid accidents or objects in the roadway. When experiencing a hard, quick turn the vehicle body tends to elevate on one side and lower on the opposite side very suddenly. This condition is referred to as vehicle body roll. High profile vehicles such as trucks, sports utility vehicles, vans, all-terrain vehicles (ATVs) and the like experience roll conditions more readily than lower profile vehicles, such as passenger cars.
A variety of suspension and stabilizer systems have been used on vehicles of all types to improve passenger comfort and driving stability. Primary suspension system components can include springs and/or dampers providing spring force to suspend the vehicle body, controlling a single wheel assembly and movement relative to the vehicle frame. Primary suspension systems provide only minimal resistance to vehicle body roll. Roll stabilizer systems provide spring force to return the vehicle body to a neutral position or condition when forces from sudden vehicle movements have caused the body to lean one direction or another. Several types of stabilizer systems are known.
Torsion bar stabilizer systems have a stabilizer bar as a tension spring and links in series attached to the primary suspension system and vehicle frame. Single compensating stabilizer systems have one anti-roll compensator attached to the primary suspension via a bell crank or the like on each control arm. A dual compensating linear stabilizer system has two anti-roll compensators attached to the primary suspension with two bell cranks on each control arm, with each compensator attached to an upper bell crank on one control arm and to a lower bell crank on the other control arm. Stabilizer systems as described have achieved acceptance and operate effectively to return the vehicle to a neutral condition when vehicle body roll has been experienced.
For typical street and highway driving conditions it is desirable that a stabilizer system be always operating. However, off-road vehicles, including trucks, ATVs and the like, can be operated in severe terrain where one or more wheel may be severely displaced with respect to the other wheels. Commonly, operation in the most severe terrain conditions is performed at low speeds. It is desirable in some situations to operate without a stabilizer system so that the wheels can move independently, without interference or resistance from spring members in the stabilizer system. However, these same vehicles also may be operated on highways or in other high-speed conditions. The high profiles of such vehicles can result in the vehicle being more prone to roll than other vehicles. Accordingly, it is desirable that such vehicles have stabilizer systems for such high-speed operation. Disconnecting or removing stabilizer systems when vehicles are taken off road has been difficult and time consuming.
United States Patent Application Publication 2007/0045978 discloses structures and systems whereby stabilizers can be placed in active, operating conditions; and inactive, non-operating conditions as desired. In one embodiment disclosed therein a stabilizer includes a rotatable outer housing with fixed end caps. A rod extends into the housing through one end cap. Within the housing, a spring is disposed on the rod between washers. End stops connected to the housing for rotation therewith are disposed in the housing axially outwardly of the washers. The end stops define a central opening and outwardly extending channels from the central opening. Lands separate the channels. Each washer has a shape complementary to the shapes of the openings in the end stops and includes outwardly extending lobes. Depending on the relative rotational positions of the end stops relative to the washers, lobes on the washers are aligned either with lands or channels on the end stops. To activate and deactivate the stabilizer, the housing is rotated to rotate the end stops and align either the channels or the lands of the end stops with the lobes of the washer. Accordingly, upon axial movement of the rod, the washers and spring move axially relative to the end stops if the lobes of the washer are aligned with the channels of the end stops, and to the stabilizer is rendered in active. Conversely, if the lobes of the washers are aligned with the lands of the end stops, axial movement of the rod causes compression of the spring, and the stabilizer is active within the system.
While the stabilizers disclosed in the aforementioned published patent application can be used effectively as a system that can be coupled and decoupled selectively; the exposed, externally rotating parts can be undesirable. The decoupling stabilizers as described as therein can be difficult to seal from ambient conditions such as snow, rain, standing water, mud and dirt. Since the vehicles on which a decoupling stabilizer can be used advantageously maybe used off road and in adverse conditions, adequate sealing against contaminant intrusion is desirable.